Scribe process and scribe device

ABSTRACT

A scribe device comprises a body ( 10 ). A holder ( 20 ) is supported by the body ( 10 ) such that the holder ( 20 ) can slightly slide in a direction of a slide axis (Lb) which intersects a surface of a workpiece ( 100 ). Retaining portions ( 15, 21 ) spaced apart in a direction of the slide axis (Lb) are formed on the body ( 10 ) and the holder ( 20 ), respectively. A vibratory actuator ( 40 ) is sandwiched between the retainer portion of the body and the retainer portion of the holder. The holder ( 20 ) holds an abutment member ( 30 ). The holder is biased by a biasing member ( 23 ) such that said retaining portion of the holder is pressed against the vibratory actuator. The vibratory actuator renders the vibrations in the direction of the slide axis to the holder. The abutment member transmits the vibrations from the holder to the workpiece. That is, the abutment member ( 30 ) is subjected to a static force and a vibration energy and pressed against the workpiece ( 100 ). In that state, the abutment member ( 30 ) is relatively moved with respect to the workpiece ( 100 ) to thereby form a scribe line in the workpiece.

BACKGROUND OF THE INVENTION

[0001] This invention relates to a scribe process and a scribe devicefor forming a scribe line on a surface of a workpiece of a hard materialsuch as a sheet glass, or the like.

[0002] In general, in case a workpiece such as a sheet glass or the likeis caused to be fracture, a scribe line is preliminarily formed on thesurface of the workpiece and the workpiece is caused to be fracturealong this scribe line. A conventional scribe device used for formingsuch a scribe line is disclosed, for example, in Japanese Utility ModelUnexamined Publication No. Hei 1-110234. Specifically, as shown in FIG.22, the conventional scribe device comprises a disc-shaped cutter 90(abutment member) with a sharpened peripheral edge, a holder 91rotatably supporting the cutter 90, and a pressing/moving mechanism (notshown) for pressing the cutter 90 against a surface of a sheet glass 100(workpiece) through the holder 91 and moving the cutter 90 along thesurface of the sheet glass 100.

[0003] A scribe line 105 is formed by moving the cutter 90 pressedagainst the sheet glass 100 as described above. The scribe line 105includes, as shown in FIG. 22A, an edge entry portion 105 a, a rib mark105 b, and a vertical crack 105 c. In order to facilitate a fracture ofthe sheet glass 100, it is necessary to form the vertical crack 105 cdeeply. For this purpose, it suffices that the force for pressing thecutter 90 against the sheet glass 100 is increased. However, if thecutter 90 is pressed against the sheet glass 100 with an increasedpressing force, there is a possibility that the scribe line 105including not only the vertical crack 105 c but also a horizontal crack106 extending leftwardly and rightwardly from the scribe line 105 tendto occur as shown in FIG. 22B, thus unfavorably resulting in a cut, apeel-off, or the like formed in the vicinity of the scribe line 105 dueto the horizontal crack 106.

[0004] In contrast, if the force for pressing the cutter 90 against thesheet glass 100 is decreased, the horizontal crack 106 does not occurbut a sufficiently large depth of the vertical crack 105 c becomesunobtainable. This means that the intended favorable fracture of thesheet glass 100 is unobtainable.

SUMMARY OF THE INVENTION

[0005] It is an object of the present invention to provide a scribedevice capable of forming a deep and beautiful scribe line.

[0006] The subject matter of the present invention resides in a scribeprocess for scribing a surface of a workpiece by applying vibrations tothe workpiece while pressing an abutment member against the surface ofthe workpiece.

[0007] In a device for carrying our this process, a holder is supportedby a body such that the holder can slightly slide in a direction of aslide axis which intersects a surface of a workpiece. Retainer portionsspaced apart in the direction of the slide axis are each formed on thebody and the holder, respectively. A vibratory actuator is sandwichedbetween the retainer portion of the body and the retainer portion of theholder. The holder holds an abutment member. The holder is biased by abiasing member such that the retainer portion of the holder is pressedagainst the vibratory actuator. The vibratory actuator rendersvibrations in the direction of the slide axis to the holder. Theabutment member transmits the vibrations from the holder to theworkpiece. When the body or the workpiece is moved, either manually orby a moving mechanism, relative to each other in that state, a scribeline is formed.

[0008] In a modified device, the body is attached with an elastic armand an abutment member is attached to a distal end portion of theelastic arm. Vibrations of a vibratory actuator are transmitted to theabutment member through the elastic arm.

BRIEF DESCRIPTION OF THE DRAWINGS

[0009]FIG. 1 is a front view of a scribe device according to the firstembodiment of the present invention;

[0010]FIG. 2 is a vertical sectional view of the scribe device taken online II-II of FIG. 1;

[0011]FIG. 3 is a plan view of the scribe device;

[0012]FIG. 4A is a front view, partly in section, of a case member of abody of the scribe device,

[0013]FIG. 4B is a sectional view taken on line IV-IV of FIG. 4A, and

[0014]FIG. 4C is a bottom view;

[0015]FIG. 5A is a front view of an attachment holding a cutter in thescribe device,

[0016]FIG. 5B is a sectional view taken on line V-V of FIG. 5A, and

[0017]FIG. 5C is a bottom view of the attachment;

[0018]FIG. 6 is a cross-sectional view taken on line VI-VI of FIG. 1;

[0019]FIG. 7 is a bottom view of the cutter and a guide plate of thescribe device;

[0020]FIGS. 8A and 8B are enlarged sectional views sequentially showingthe process for guiding the cutter to an end edge of a sheet glass;

[0021]FIG. 9 is an enlarged sectional view showing the cutter, the guideplate and the sheet glass formed with a scribe line;

[0022]FIG. 10 is a graph showing a force for pressing the cutter againstthe sheet glass;

[0023]FIG. 11 is an enlarged sectional view taken along the scribe lineformed on the sheet glass;

[0024]FIG. 12 is a schematic view showing a general construction of adevice for fracturing the sheet glass formed with the scribe line;

[0025]FIG. 13 is a vertical sectional view of a scribe device accordingto the second embodiment of the present invention;

[0026]FIG. 14 is a front view, partly in section, of a scribe deviceaccording to the third embodiment of the present invention;

[0027]FIG. 15 is a schematic view showing a relation between a directiontowards which a pressing force and a vibratory energy are rendered and adirection of movement of a workpiece in the third embodiment;

[0028]FIG. 16 is a sectional view of a main portion of a scribe deviceaccording to the fourth embodiment of the present invention;

[0029]FIG. 17 is a view showing another mode of a process for forming ascribe line using the scribe device;

[0030]FIG. 18 is a view showing still another mode of a process forforming a scribe line using the scribe device;

[0031]FIG. 19 is a schematic view of a scribe device according to thefifth embodiment of the present invention;

[0032]FIG. 20 is a schematic view of a scribe device according to thesixth embodiment of the present invention;

[0033]FIG. 21 is a schematic view showing a process for forming a scribeline on each surface of a liquid crystal cell using two of the scribedevices of FIG. 19;

[0034]FIG. 22A is a front view, partly in section, of a scribe deviceaccording to the prior art, and FIG. 22B is a side view of the scribedevice.

DETAILED DESCRIPTION OF THE EMBODIMENTS

[0035] The first embodiment of the present invention will now bedescribed with reference to FIGS. 1 to 11.

[0036] As shown in FIGS. 1 and 2, a scribe device comprises a movabletable 1 (support table), a moving mechanism 2 for horizontally movingthe movable table 1, a slide mechanism 3 disposed on the movable table1, a body 10 vertically slidably supported by the slide mechanism 3, aholder 20 vertically slightly slidably supported by the body 10, acutter 30 (abutment member) disposed on a lower end of the holder 20,and a piezo-actuator 40 (vibratory actuator) for rendering verticalvibrations to the holder 20.

[0037] The above component elements will be described hereinafter in asequential manner. The moving mechanism 2 moves the movable table 1horizontally, i.e., in a left and right direction in FIG. 1 and in anorthogonal direction to the surface of paper in FIG. 2.

[0038] The slide mechanism 3 comprises a guide 4, and a slider 5. Theguide 4 is fixed to the movable table 1 through a square attachmentplate 6. The guide 4 has a guide groove 4 a extending vertically. Thevertically long slider 5 has a tongue 5 a insertable into the guidegroove 4 a. Owing to this arrangement, the slider 5 is verticallyslidably supported by the guide 4. The slider 5 is defined its lowermostposition by a stopper (not shown).

[0039] As shown in FIGS. 2 and 3, the body 10 is attached to the slider5 through a pair of upper and lower horizontal plate springs 7 a, 7 b(vibration attenuating member having elasticity). Specifically, an upperand a lower bracket 8 a, 8 b are fixed to the slider 5. The platesprings 7 a, 7 b are fixed at their centers to the plate springs 7 a, 7b, respectively. On the other hand, a pair of upper and a pair of lowerbrackets 9 a, 9 b are fixed to the body 10, respectively. The pair ofupper brackets 9 a are disposed on opposite sides of and away from theupper bracket 8 a and fixed to opposite ends of the plate spring 7 a.Similarly, the pair of lower brackets 9 b are also disposed on oppositesides of and away from the bracket 8 b and fixed to opposite ends of theplate spring 7 b.

[0040] Either one or both of the plate springs 7 a, 7 b may be fixed attheir centers to the body 10 with opposite ends thereof fixed to theslider 5 side.

[0041] The upper bracket 8 a projects upwardly and detachably attachedat its upper end face with a weight 50. That is, a vertical through-hole50 a is formed in the weight 50. A screw 51 is inserted into thisthrough-hole 50 a and screwed into a screw hole 8 x formed in an upperend face of the bracket 8 a. By doing so, the weight 50 can be attachedto the upper bracket 8 a.

[0042] The weight 50 is detachably attached with a cylindrical vibrationsensor 55. That is, a receiving hole 50 b is formed in a lateral surfaceof the weight 50, and the vibration sensor 55 is received in thisreceiving hole 50 b. A vertical screw hole 50 c is formed in the weight50. A screw 56 (only shown in FIG. 3) is screwed into the screw hole 50c and presses at its distal end an outer peripheral surface of thevibration sensor 55. By doing so, the vibration sensor 55 is fixed tothe weight 50.

[0043] The body 10 has a vertically elongated square plate 11, a casemember 12 fixed to a front surface of an upper portion of this plate 11,and a guide 11 fixed to a front surface of a lower portion of the plate11. A receiving hole 13 is defined by the plate 11 and the case member12. A retaining portion 15 comprised of a shallow recess for thepiezo-actuator 40 is formed in a lower end of the case member 12.

[0044] The holder 20 exhibits a vertically extending planarconfiguration having a small width. An intermediate portion of thisholder 20 is in engagement with a vertically extending guide groove 13 aformed in the guide 13. Owing to this arrangement, the holder 20 issupported by the body 10 such that the holder 20 can slightly slide in avertical direction. In this embodiment, a center axis Lb of the holder20 vertically extends in parallel relation to the slide axis. Aretaining member 21 (retaining portion of the holder 20) is fixed to afront surface of a longitudinally intermediate portion of the holder 20.The piezo-actuator 40 is vertically elongated and exhibits a squareconfiguration in section. An upper end of the piezo-actuator 40 isengaged with and retained by the retaining portion 15 of the body 10,while a lower end thereof is retained by the retaining member 21 of theholder 20. In other words, a center axis La of the piezo-actuator 40vertically extends in parallel relation to the center axis Lb of theholder 20 and the piezo-actuator 40 is sandwiched between the retainingportion 15 and the retaining member 21. The piezo-actuator 40 issubjected to high frequency ac voltage and cyclically expanded andcontracted in a vertical direction. This cyclical expansion andcontraction causes the holder 20 to be vibrated in the verticaldirection.

[0045] Fixed to a lower end of the piezo-actuator 40 is a support member45 having a spherical lower surface. The lower surface of the supportmember 45 is in contact with a conical or spherical retaining surface 21a formed on the retaining member 21. Owing to this arrangement, thevibrations of the piezo-actuator 40 can be delivered uniformly in thedirection of the center axis Lb of the holder 20, i.e., in the directionof the slide axis.

[0046] A vertically upwardly extending rod 22 is connected to an upperend of the holder 20 through a pin 22 x.

[0047] The rod 22 pierces through an upper wall of the case member 12 ofthe body 10 and projects upwardly. A ball 23 (spherical biasing member)made of elastic material such as rubber, resin, or the like, and anupper and a lower retaining seat 24, 25 are arranged on the upper wall.The retaining seats 24, 25 have spherical surfaces and are located on anupper and a lower side of the ball 23, respectively, They are supportedin the states pierced by the rod 22.

[0048] A male screw 22 a is formed on an upper end portion of the rod22. The upper retaining seat 24 is threadingly engaged with the malescrew 22 a. By tightening this retaining seat 24, the ball 23 issandwiched between the retaining seats 24, 25 with the lower retainingseat 25 abutted with an upper surface of the case member 12, so that theball 23 is elastically deformed. A restoring force of the ball 23 isserved as a force for biasing the holder 20 upwardly with respect to thebody 10, and therefore, as an elastic force normally applied to thepiezo-actuator 40 through the retaining member 21 of the holder 20.

[0049] The male screw 22 a is further threadingly engaged with a locknut 26, so that the upper retaining seat 24 is prevented from gettingloosened. The upper retaining seat 24 may merely be pierced through therod 22 without being threadingly engaged with the rod 22. In that case,the ball 23 is elastically deformed by tightening the lock nut 26.

[0050] The holder 20 is biased upwardly by elasticity of the ball 23.Since this biasing force causes the retaining member 21 to press thepiezo-actuator 40, the piezo-actuator 40 is stably supported by the body10. The holder 20 can slide (movable) vertically within a range ofelastic deformation of the ball 23. The above expression “can slightlyslide” refers to this sliding movement.

[0051] A cooling structure for the piezo-actuator 40 will now bedescribed in detail. As best shown in FIG. 4, an air passageway 16 isformed in the case member 12 of the body 10. One open end 16 a of theair passageway 16 is located on a side surface of the case member 12. Acompressed air source 18 (air pressure source) is connected to this openend 16 a through a joint 17.

[0052] The air passageway 16 horizontally extends from the one open end16 a and is bifurcated and extends downwardly. The other open ends 16 bare located on a lower surface of the case member 12. More specifically,the other open ends 16 b are located on two corners of the retainingportion 15. An upper end of the piezo-actuator 40 partly blocks the twoopening ends 16 b. A cover 19 having a generally U-shape incross-section for covering the front surface and two side surfaces ofthe piezo-actuator 40 is attached to an outer surface of a lower endportion of the case member 12. Between the cover 19 and thepiezo-actuator 40, there is formed a gap 19 a. An upper end of this gap19 a is in communication with the other open end 16 b of the airpassageway 16, while a lower end thereof is opened.

[0053] An attachment structure of the cutter 30 will now be described.The cutter 30 is attached to a lower end portion of the holder 20through an attachment 60. As shown in FIG. 5, the attachment 60 has anupper attachment portion 61 and a lower grip portion 62.

[0054] The attachment portion 61 of the attachment 60 has two upstandingwalls 61 a, 61 b and exhibits a U-shape in vertical section. As shown inFIG. 2, a lower end portion of the holder 20 enters between theupstanding walls 61 a, 61 b. A screw 63 is pierced through theupstanding wall 61 a of the attachment portion 61 and the lower endportion of the holder 20 and is screwed into the other upstanding wall61 b, thereby the attachment 60 is connected to the lower end portion ofthe holder 20.

[0055] In a state where the screw 63 is untightened, the attachment 60can pivot about the screw 60 with respect to the holder 20. When thescrew 63 is tightened and a screw 64 is screwed into the upstanding wall61 a to press the distal end thereof against the lower end portion ofthe holder 20, the attachment 60 is fixed to the holder 20. In this way,the attachment 60 can be adjusted in angle with respect to the centeraxis Lb (slide axis) of the holder 20.

[0056] The grip portion 62 of the attachment 60 has two parallel pieces62 a, 62 b and exhibits a U-shape in cross-section as shown in FIGS. 5and 6. Between the pieces 62 a, 62 b, a sectionally square base portion31 of the cutter 30 is received. In that state, the screw 65 is piercedthrough a distal end portion of the piece 62 a of the grip portion 62and screwed into a distal end portion of the other piece 62 b so thatthe both pieces 62 a, 62 b are brought closer to each other. Then, bytightening the base portion 31 between the two pieces 62 a, 62 b, thecutter 30 is detachably fixed to the attachment 60.

[0057] The grip portion 62 has a horizontal lock wall 62 c. In a statewhere the cutter 30 is fixed, the upper surface of the base portion 31is in contact with the lock wall 62 c.

[0058] The cutter 30 has the base portion 31, and a tip portion 32 fixedto a center of the lower surface of the base portion 31. A center axisLc of the tip portion 32 vertically extends in parallel relation to thecenter axis Lb of the holder 20. A lower end (forward end) of the tipportion is formed in a conical configuration and sharpened. The lowerend of the tip portion 32 may be formed in a pyramidal configuration. Apyramidal diamond grain is firmly secured to a lower end of the cutter30. A top of this diamond grain faces just under so that it contacts asurface of a sheet glass 100 as later described.

[0059] A guide plate 35 (guide member) is attached to the attachment 60.This guide plate 35 is formed of a U-shaped plate spring. Opposite endportions of the guide plate 35 are terminated in flat fixture portions35 a, and a central portion of the guide plate 35 is formed in aconvexly curved guide portion 35 b. The pair of fixture portions 35 aare fixed to opposite side surfaces of the attachment portion 62 of theattachment 60.

[0060] As shown in FIGS. 1 and 7, a hole 35 c is formed in a centralportion of the guide portion 35 b. The tip portion 32 of the cutter 30passes through this hole 35 c and projects a predetermined amount(indicated by H of FIG. 8) downwardly from the guide portion 35 b. InFIG. 8, the projected amount is illustrated in an exaggerated manner.

[0061] As shown in FIGS. 1 and 3, the attachment plate 6 is attachedwith an air-cylinder 70 (push-up mechanism) in a vertical manner. On theother hand, an L-shaped bracket 75 is fixed to a side surface of thecase member 12 of the body 10. A vertical short rod 76 is threadinglyengaged with the bracket 75. This short rod 76 and an upper end of therod 71 of the air cylinder 60 are confronted with each other.

[0062] Operation of the scribe device thus constructed will now bedescribed. As shown in FIG. 8, a sheet glass 100 (workpiece) ishorizontally set in place on a horizontal installation table 80. In aninitial state, the cutter 30 of the scribe device is horizontally awayfrom the edge of the sheet glass 100 and located in the lowermostposition (position corresponding to the lowermost position of the slider5). In that state, when the moving mechanism 2 is driven to move themovable table 1 in the horizontal direction (direction as indicated byan arrow of FIG. 8), the body 10, the holder 20, and the cutter 30 arecaused to move in unison in the same direction. Then, as shown in FIG.8A, the curved guide portion 35 b of the guide plate 35 attached to theholder 20 comes into contact with an end edge of the sheet glass 100.When the movable table 1 is further moved, the guide portion 35 b ispushed up along the inclination of the guide portion 35 b while beingcontacted with the end edge of the sheet glass 100, and thus, the slider5, the body 10, the holder 20 and the cutter 30 are also pushed up.Before long, the cutter 30 arrives at the end edge of the sheet glass100 as shown in FIG. 8B. By further slightly moving the table 1 in thedirection as indicated by the arrow, the lower end of the tip portion 32is placed on the upper surface of the sheet glass 100 through the taperof the tip portion 32 of the cutter 30.

[0063] As mentioned above, in the state where the cutter 30 is placed onthe upper surface of the sheet glass 100 at an area in the vicinity ofthe end edge thereof, the cutter 30 is normally rendered a force forpressing the upper surface of the sheet glass 100. This pressing forceis attributable to the dead weights of the body 10, the holder 20, theslider 5, the weight 50, etc.

[0064] As mentioned above, the scribing is carried out in the statewhere the cutter 30 is pressed against the surface of the sheet glass100 by the dead weights of the body 10, etc. That is, the movingmechanism 2 is driven to move the movable table 1 so that the cutter 30is moved in the direction as indicated by the arrow of FIG. 8 (in thedirection perpendicular to the surface of paper in FIG. 9). Then, a highfrequency voltage is applied to the piezo-actuator 40, so that thepiezo-actuator 40 is cyclically expanded and contracted. Then, thevibrations of the holder 20 caused by the cyclical expansion andcontraction of the piezo-actuator 40 are transmitted to the sheet glass100 through the cutter 30. In other words, as shown in FIG. 10, thepressing force P applied to the sheet glass 100 through the cutter 30 isobtained by adding a force due to vibrations of the piezo-actuator 40 tothe static force P1 due to dead weights of the body 10, etc.Accordingly, the pressing force P cyclically becomes a very large forceand applies a shock to the sheet glass 100 through the sharpened lowerend of the cutter 30. As a result, a scribe line 105 having a deepvertical crack 105 c can be formed in the sheet glass 100 as shown inFIG. 11. However, since the static force P1 is comparatively small, ahorizontal crack, which occurs in the conventional device, hardlyoccurs.

[0065] Incidentally, the scribe line 105 formed by this embodiment has,unlike the prior art, a bear-like rib mark 105 b as shown in FIG. 11.

[0066] The cycle of the pressing force P, in other words, the frequencyof the high frequency voltage applied to the piezo-actuator 40 is setsto about 3 to 30 KHz, and the expanding/contracting amount of thepiezo-actuator 40, that is, the amplitude of the vibrations is set toabout a few μm to 20 μm. depending on the hardness, thickness, etc. ofthe material of the sheet glass 100. The feed speed of the cutter 30 ispreferably set to about 100 to 250 mm/sec in case the above frequency isemployed.

[0067] In the forming process of the scribe line 105, since the cutter30 is normally contacted with the surface of the sheet glass 100 by thepressing force caused by the dead weight of the body 10, etc. and neverinstantaneously separated from the surface of the sheet glass 100, abeautiful scribe line 105 can be formed by eliminating any damageoccurrable to the area in the vicinity of the scribe line 105. Since theholder 20 is rigid and the cutter 30 is attached directly to the holder20, the cutter 30 is vibrated in unison with the holder 20, and thevibration energy of the piezo-actuator 40 can be transmitted to thecutter 30 favorably. Moreover, a possibility of resonance can be reducedand a possibility of leap-up of the cutter 30 can be reduced.

[0068] Furthermore, in this embodiment, since the plate springs 7 a, 7 bare interposed between the body 10 and the slider 5 to attenuatevibrations, the possibility of resonance can be reduced moreeffectively.

[0069] Since the ball 23 is used as a biasing member, durability is goodand an elastic force can positively be applied to the piezo-actuator 40.

[0070] In this embodiment, since the weight 50 is detachably attached tothe slider 5, the static force P1 can be increased in accordance withnecessity, that is, depending on material, hardness, thickness, etc. ofthe sheet glass 100. Moreover, by changing this weight 50, the staticforce P1 can be changed.

[0071] The dead weights of the slider 5 and the weight 50 are applied tothe cutter 30 through the plate springs 7 a, 7 b. In other words, sincethe vibrations of the piezo-actuator 40 and a reaction received by thecutter 30 from the sheet glass 100 are attenuated by the plate springs 7a, 7 b, the static force P1 caused by the slider 5 and the weight 50 canbe stabilized.

[0072] The vibration sensor 55 attached to the weight 50 detects thevibrations transmitted to the slider S and sends them to a motor notshown. A vibration waveform is displayed in a monitor. The operatoradjusts the frequency of the high frequency voltage to be applied to thepiezo-actuator 40 so that the amplitude of the vibration waveform willnot become extremely large due to resonance, and preferably, theamplitude will be minimized. By doing so, the possibility of resonancecan more positively be eliminated.

[0073] Since the vibrations of the piezo-actuator 40 is transmitted tothe vibration sensor 55 after being attenuated by the plate springs 7 a,7 b, the vibration sensor 55 can positively detect an increased portionof the vibrations caused by resonance.

[0074] The vibration sensor 55 may be disposed on the body 10.

[0075] During the time the piezo-actuator 40 is driven, a compressed airis supplied to the air passageway 16 of the body 10 from the compressedair source 19. By this, air is jetted towards the piezo-actuator 40 fromthe open end 16 b of the air passageway 16. The air thus jetted passesthrough the gap 19 a between the piezo actuator 40 and the cover 19 andis discharged from the lower end of the gap 19 a. At that time, sincethe air flows along the front surface and both side surfaces of thepiezo-actuator 40, it can cool the piezo-actuator 40. Accordingly, afailure due to excessive heating of the piezo-actuator 40 can beprevented.

[0076] When the formation of the scribe line on the sheet glass 100 iscompleted by the cutter 30, the supply of an electric current to thepiezo-actuator 40 is stopped and the air-cylinder 70 is driven to pushup the body 10, thereby the cutter 30 is separated from the workpiece100. Then, the sheet glass 100 is removed from the installation table80. Thereafter, the movable table 1 is returned to its initial positionand the air-cylinder 70 is driven in-a reversed direction so that it isreturned to a state of FIG. 1, i.e., a state where the upper end of therod of the air-cylinder 50 is separated from the short rod 56. By doingso, the body 10 is returned to its lowermost position. Then, in the samemanner as mentioned above, a new sheet glass 100 for the next operationis set to the installation table 80 and the scribe line formingprocedure is carried out again.

[0077] Operation of the attachment 60 will now be described. Asdescribed previously, the attachment 60 can be adjusted in angle. Incase the hardness of the sheet glass 100 is high, the center axis Lc ofthe tip portion 32 of the cutter 30 is brought into a vertical postureso as to be orthogonal to the surface of the sheet glass 100. By doingso, a deep vertical crack can be formed. In case the hardness of thesheet glass 100 is low, the center axis Lc of the tip portion 32 isinclined towards the moving direction of the cutter 30 by adjusting theangle of the attachment 60. In other words, the center axis Lc isinclined towards the opposite side to the movement of the sheet glass100 relative to the cutter 30. By doing so, a sinking amount of the tipportion 32 into the sheet glass 100 can be reduced so that it will notbe caught by the sheet glass 100.

[0078] When the diamond grain of the tip portion 32 of the cutter 30 wasworn out, the screw 65 is untightened to remove the cutter 30 from theattachment 60, so that the cutter 30 can easily be replaced by a newone.

[0079] For the purpose of reference, the sheet glass 100 formed with thescribe line 105 is fractured using a fracturing device of FIG. 12. Thisfracturing device is comprised of an installation table 150, and anevacuating device 160. A shallow recess 151 is formed in an uppersurface 150 a of the installation table 150. This recess 151 extends ina direction orthogonal to the surface of paper. The length of the recess151 is set to be slightly shorter than an entire length of the scribeline 105.

[0080] A groove 152 is formed in an upper surface 150 a of theinstallation table 150 in such a manner as to surround the recess 151.An O-ring 153 is fitted in this groove 152. An evacuating hole 154communicating with the recess 151 is formed in the installation table150. One end of a communicating tube 165 of the evacuating device 160 isconnected to the evacuating hole 154. The other end of the communicatingtube 165 is connected to an air opening tube 166 which is open toatmospheric air through a first solenoid valve V1, and a suction tube168 communicating with a vacuum tank 167 through a second solenoid valveV2. The vacuum tank 167 is connected to a vacuum pump (not shown), sothat a high degree of evacuation is normally maintained.

[0081] In case the sheet glass 100 is fractured using this fracturingdevice, the sheet glass 100 is placed on the upper surface 150 a of theinstallation table 150 such that the sheet glass 100 may intimatelycontacts the O-ring 153 on the surface 150 s of the installation table150. At that time, the scribe line 105 is directed downwardly andpositioned in the widthwise center of the recess 151. Then, the firstand second solenoid valves V1 and V2 are alternately repeatedly openedand closed at a short cycle, so that a shocking suction force isrepeatedly acted on a lower surface of the sheet glass 100 alreadyformed with the scribe line 105. By this, the sheet glass 100 can befractured along the scribe line. As mentioned above, since the scribeline 105 is formed deeply and beautifully, the fracture can be carriedout along the scribe line 105 easily and positively.

[0082] Other embodiments of the present invention will now be described.In those embodiments to be described hereinafter, those component partscorresponding to the first embodiment are denoted by the same referencenumerals and detailed description thereof is omitted.

[0083]FIG. 13 shows the second embodiment of the present invention. Thelargest difference of this second embodiment from the first embodimentresides in that the center axis La of the piezo-actuator 40 iscoincident with the center axis Lb of the holder 20 and forms a linearline. Specifically, a through-hole 20 a (receiving space) is formed inthe holder 20 in its widthwise direction. This through-hole 20 exhibitsan elongated square configuration extending in a longitudinal directionof the holder 20. The piezo-actuator 40 is received in this through-hole20 a.

[0084] A central portion of a lower edge of the through-hole 20 a isserved as a retainer portion 21′. This retaining portion 21′ is formedin a conical surface or a spherical surface so that the support member45 attached to the lower end of the piezo-actuator 40 can be retainedefficiently. On the other hand, a tongue 15′ is formed at the lower endof the case member 12 of the body 10. This tongue 15′ is entered into anupper end portion of the through-hole 20 a and served as a retainingportion for retaining the upper end of the piezo-actuator 40.

[0085] In the second embodiment, since the center line La of thepiezo-actuator 40 is in alignment with the center axis Lb of the holder20, the vibrations of the piezo-actuator 40 can be transmitted to theholder efficiently.

[0086]FIG. 14 shows the third embodiment of the present invention. Inthis embodiment, the attachment plate 6 is fixed to the support table 86through the bracket 85. The bracket 85 exhibits an L-shapedconfiguration in plan view. A plate portion 85 a of the bracket 85 isfixed to the support table 86 by two upper screws 87 and two lowerscrews 87. An attachment plate 6 is fixed to the other plate portion 85b. A washer 88 is interposed between the plate portion 85 a and thesupport table 86. The plate portion 85 a is inclined relative to avertical plane by this washer 88. The upper screws 87 are piercedthrough this washer 88. The inclination of the bracket 85 is adjusted bythe thickness of this washer 88. In FIG. 14, the inclination of thebracket 85 is illustrated in an exaggerated manner.

[0087] The inclination of the bracket 85 causes the inclination of thecomponent elements disposed on the attachment plate 6, i.e., the guide 4and the slider 5 of the slide mechanism 3, the body 10 and the holder20. That is, the center axis Lb (the slider axis) of the holder 20, theslide axis of the slider 5 and the center axis La (the vibration axis)of the piezo-actuator 40 are inclined.

[0088] In the third embodiment, the installation table 80 is moved bythe moving mechanism 2, thereby the sheet glass 100 is movedhorizontally relative to the cutter 30. The center axis Lb (slide axis)of the holder 20 is inclined in the opposite direction to the relativemovement direction of the sheet glass 100. That is, in case the sheetglass 100 horizontally proceeds leftwardly as shown in FIG. 14, thecenter axis Lb of the holder 20 is fallen rightwardly of a vertical axis(axis orthogonal to the moving direction of the sheet glass 100).

[0089] In the third embodiment, since the center axis Lb of the holder20 is inclined, the pressing force P and the vibration energy from thecutter 30 to the sheet glass 100 are given from the inclined directionas shown in an exaggerated manner in FIG. 15. In other words, they aresupplied towards the vertical crack 105 c in such a manner as to growthe vertical crack 105 c. Therefore, the deep vertical crack 15 c can beformed more positively.

[0090] In the third embodiment, the inclination of the center axis Lc(center axis of the cone or pyramid) of the tip portion 32 of the cutter30 with respect to the sheet glass 100 can be adjusted by adjusting theangle of the attachment 60. That is, in case the hardness of the sheetglass 100 is high, the center axis Lc of the tip portion 32 is broughtinto a correct or nearly correct right angle to the surface of the sheetglass 100 by redusing the angle of intersection between the center axisLc of the tip portion 32 and the center axis Lb of the holder 20 asshown in FIG. 14. In case the hardness of the sheet glass 100 is low,the angle of intersection between the center axis Lc of the tip portion32 and the center axis Lb of the holder 20 is increased, thereby theinclination of the center axis Lc of the tip portion 32 with respect tothe sheet glass 100 is increased.

[0091] In the third embodiment, instead of inclining the bracket 86, theguide 4 (see FIG. 1) fitted to the attachment plate 6 may be inclined.

[0092]FIG. 16 shows a main portion of the fourth embodiment. In thisfourth embodiment, the air-cylinder 59 (biasing mechanism, pressingmeans) is fixed, either directly or through the attachment plate 6, tothe support table 1, for example, and a distal end of the rod isconnected to or abutted with the slider 5. By driving the air-cylinder59, the slider 5 and the body 10 are biased towards the surface of theworkpiece. Use of this air-cylinder 59 makes it possible to carry outthe scribing operation with the holder 20 fallen in a horizontal postureand the workpiece held in a vertical posture.

[0093] In the first, second and fourth embodiment, it is also acceptablethat the support table 1 for supporting the body 10 is fixed in placewithout being moved horizontally, the moving mechanism 2 is connected tothe installation table 80, and the sheet glass 100 placed on theinstallation table 80 is moved. In the third embodiment, the supporttable 85 may be moved rightwardly in FIG. 14.

[0094] Instead of the ball 23, a plurality of coned disc springssuperimposed one upon another, or the like may be used as the biasingmember.

[0095] The body 10 may be fixed, directly and not through the platesprings 7 a, 7 b, to the slider 5. It is also an interesting alternativethat the body 10 is integral with the slider 5.

[0096] A vacuum mechanism may be used as the air pressure source. Inthat case, the air flows in the opposite direction to the air-flowdescribed in the above embodiments.

[0097] The movement of the body 10 relative to the workpiece or themovement of the workpiece relative to the body 10 may be manuallycarried out by the operator. Similarly, the pressing force to the cutter30 may be manually applied by the operator through the body 10.

[0098] In the embodiment of FIG. 17, a recess 80 a is formed in theinstallation table 80. The sheet glass 100 is placed on the installationtable 80 such that an area of the sheet glass 100 to be formed with thescribe line is coincident with the recess 80 a, and the scribingoperation is performed in that state. By doing so, even if the flatnessof the sheet glass 100 and he flatness of the installation table 80 areinferior, the vibration energy can be applied to the sheet glass 100 ina stable manner.

[0099] As shown in FIG. 18, a compression layer 100 a (layer where acompressive stress is present as an internal stress) is present in athickness-wise central portion of the sheet glass 100. In case the sheetglass 100 is thin, a scribe line is preferably formed in such a mannerthat the vertical crack 105 c transverses the compression layer 100 a.By doing so, the vertical crack grows in a natural manner after thescribe line is formed, as indicated by the broken line. Therefore, theworkpiece can be fractured without a need of the fracturing processdiscussed above.

[0100]FIG. 19 shows a scribe device according to the fifth embodiment ofthe present invention. This scribe device includes a generally U-shapedbody 110. The body 110 is fixed to a support frame, etc., not shown. Twoprojections 111 are formed on a lower end face of the body 110 in such amanner to be spaced apart from each other. Supported on thoseprojections 111 are one end portion and an intermediate portion of anelastic arm 150 extending horizontally through a support axis 112. Thebase portion 31 of the cutter 30 is detachably attached to the other endportion (free end portion) of the elastic arm 150.

[0101] The scribe device further comprises a vibration transmittingmember 160. This vibration transmitting member 160 exhibits an invertedU-shape and a central portion 115 of the body 110 is inserted between apair of leg portions 161 thereof. The piezo-actuator 40 is sandwichedbetween a central portion 115 of the body 110 and an upper portion 165of the vibration transmitting member 160 in such a manner as to be ableto vibrate in a vertical direction.

[0102] A vibratory pin 166 is disposed between lower end portions of theleg portions 161 of the vibration transmitting member 160. Thisvibratory pin 166 is located between the two support axes 112 forsupporting the elastic arm 150 such that it is normally in abutmentrelation with a lower surface of the elastic arm 150.

[0103] Vibrations of the piezo-actuator 40 are transmitted to theelastic arm 150 through the vibration transmitting member 160 and thevibratory pin 166. Owing to this arrangement, a portion of the elasticarm 150 disposed between two support axes 112 is elastically verticallydeformed about the support axes 112, thereby the cutter 30 disposed onthe end portion of the elastic arm 150 is vibrated vertically. It shouldbe noted, however, that the cutter 30 is vibrated only when the cutter30 is in a free position where the cutter 30 is not pressed against thesheet glass 100, and the cutter 30 is almost prevented from vibrating bythe sheet glass 100 when it is pressed against the sheet glass 100. As aresult, kinetic energy of the vibrations is transformed into a force forpressing the cutter 30 against the sheet glass 100, and the cutter 30 ispressed against the sheet glass 100 by the pressing force which variescyclically.

[0104] The frame or the installation table 80 for supporting the body110 is moved horizontally, and preferably in the extending direction ofthe elastic arm 150 by a moving mechanism (not shown). By doing so, thecutter 30 relatively moves with respect to the sheet glass 100.

[0105] In the scribe device thus constructed, since the elastic arm 150is elastically deformed when it forms a scribed line, the cutter 30 ispressed against the sheet glass 100. That is, a static force is appliedto the cutter 30.

[0106]FIG. 20 shows the sixth embodiment of the present invention. Oneend portion of the elastic arm 150 is fixed to the body 110A, and thecutter 30 is attached to the other end portion of the elastic arm 150.An upper end portion of the piezo-actuator 40 is attached to the body110 and a vibration transmitting member 160A is fixed to a lower endportion of the piezo-actuator 40. This vibration transmitting member160A is abutted against an upper surface of an intermediate portion ofthe elastic arm 150.

[0107] A process for forming a scribe line in upper and lower surfacesof a liquid crystal cell 100′ (planar workpiece) comprised of twosubstrates 101, 102 will now be described with reference to FIG. 21. Inthat case, a pair of scribe device shown in FIG. 16, 19 or 20 areemployed, and the scribe lines are simultaneously formed by pressing thecutters 30 of the scribe devices against the upper and lower surfaces ofthe liquid crystal cell 100′ while applying a vibration energy thereto.The installation table 80 is formed with a hole 80 a for receivingtherein the lower abutment member 30. The installation table 80 ispreferably provided with vacuum means for supporting the liquid crystalcell 100. The liquid crystal cell 100′ formed with the scribe line inits upper and lower surfaces can easily be fractured.

[0108] In the above embodiments, the conical or pyramidal cutter 30 isemployed. However, a disc-like cutter 90 as shown in FIG. 19 may beemployed. In that case, a part of a peripheral edge of the cutter 90 isprovided as a sharpened forward end to be contacted with the workpiece.

[0109] The workpiece is not limited to the sheet glass. It may be aceramic plate, a silicon wafer, or the like.

What is claimed is:
 1. A scribe process for forming a scribe line in asurface of a workpiece by applying a vibration energy to said workpiece(100) while pressing an abutment member (30) against said surface ofsaid workpiece (100) and relatively moving said abutment member withrespect to said workpiece.
 2. A scribe process according to claim 1,wherein two scribe lines are simultaneously formed, one in a firstsurface and the other in a second surface of a planar workpiece (100′)by arranging two of said abutment members (30) likewise one on the firstsurface and the other on the second surface of said workpiece (100′). 3.A scribe device comprising: (a) a body (10) having a retaining portion(15); (b) a holder (20) supported by said body (10) such that saidholder (20) can slightly slide in a direction of a slide axis (Lb) whichintersects a surface of a workpiece (100), said holder having aretaining portion (21) spaced apart from said retaining portion of saidbody in the direction of said slide axis; (c) a vibratory actuator (40)for rendering vibrations in the direction of said slide axis to saidholder, said vibratory actuator being sandwiched between said retainingportion of said body and said retaining portion of said holder and; (d)an abutment member (32) held by said holder, said abutment membertransmitting the vibrations from said holder to said workpiece; and (e)a biasing member (23) for biasing said holder such that said retainingportion of said holder is pressed against said vibratory actuator.
 4. Ascribe device according to claim 3, further comprising a movingmechanism (2) for relatively moving said body (10) with respect to saidworkpiece (100) in a direction along the surface of said workpiece, sothat said abutment member (32) is moved relative to said surface of saidworkpiece in the same direction.
 5. A scribe device according to claim3, further comprising a slide mechanism (3) having a guide (4) and aslider (5), said slider being supported by said guide such that saidslider (5) can slide in the direction of the slide axis (Lb), said body(10) being disposed on said slider (5).
 6. A scribe device according toclaim 5, wherein said slider (5) and said body (10) are connectedtogether through a vibration attenuating elastic member (7 a, 7 b).
 7. Ascribe device according to claim 6, wherein said vibration attenuatingmember is comprised of a plate spring (7 a, 7 b).
 8. A scribe deviceaccording to one of claims 5 to 7, wherein a vibration sensor (55) isattached to said body (10) or said slider (5).
 9. A scribe deviceaccording to one of claims 5 to 7, wherein said slide axis (Lb) extendsgenerally vertically, and said abutment member (32) is pressed againstsaid surface of said workpiece (100) by dead weights of said body (10),said holder (20) and said slider (5).
 10. A scribe device according toclaim 9, wherein said slider (5) is detachably attached with weight(50).
 11. A scribe device according to claim 10, wherein said weight(50) is attached with a vibration sensor (55).
 12. A scribe deviceaccording to claim 9, further comprising a push-up mechanism (70) forpushing up said slider (5) so that said abutment member (30) isseparated from said surface of said workpiece (100).
 13. A scribe deviceaccording to one of claims 5 to 7, further comprising a biasingmechanism (59) for biasing said slider (5) towards said surface of saidworkpiece (100) so that said abutment member (30) is pressed againstsaid surface of said workpiece.
 14. A scribe device according to claim3, wherein said abutment member (30) is attached to one end of saidholder (20), and a rod (22) extending in a direction of said slide axis(Lb) is connected to the other end of said holder (20), said rodpiercing through said body (10) and projecting from said body, saidbiasing member (23) being attached to the projected portion of said rod.15. A scribe device according to claim 14, wherein said biasing memberis comprised of a ball (23) made of elastic material, and said ball (23)is sandwiched between one pair of retaining seats (24, 25) each having aspherical surface, said ball and said one pair of retaining seats arepierced therethrough by said rod (22).
 16. A scribe device according toclaim 3, wherein said body (10) is formed with an air passageway (16),one open end (16 a) of said air passageway is connected to an airpressure source (18), and the other open end (16 b) is faced with saidvibratory actuator (40).
 17. A scribe device according to claim 16,wherein said body (10) is provided with a cover (19) for covering saidvibratory actuator (40), and a gap (19 a) communicating with said airpassageway (16) is formed between said cover and said vibratoryactuator.
 18. A scribe device according to claim 3, wherein said holder(20) is formed with a receiving space (20 a), said vibratory actuator(40) is received in said receiving space, and a central axis (Lb) ofsaid holder and a central axis (La) of said vibratory actuator arealigned and extend in the direction of said slide axis.
 19. A scribedevice according to claim 3 wherein said slide axis (Lb) is inclined inan opposite direction to the direction of relative movement of saidworkpiece (100).
 20. A scribe device according to claim 3 or 19, whereinsaid holder (20) is attached with an attachment (60) such that an angleof said attachment (60) is adjustable with respect to said slide axis(Lb), and said abutment member (30) is fixed to said attachment (60).21. A scribe device according to claim 3, wherein said holder (20) isattached with an attachment (60), and said attachment (60) has a gripportion (62), said grip portion having one pair of parallel pieces (62a, 62 b) and exhibiting a U-shaped configuration in section, distal endportions of said one pair of pieces being brought closer to each otherby a screw (65) with said abutment member (30) received between said onepair of pieces of said grip portion, so that said abutment member isfixed to said attachment.
 22. A scribe device comprising: (a) a body(110); (b) an elastic arm (150) attached to said body (110), saidelastic arm having a free end portion; (c) an abutment member (30)attached to said free end portion of said elastic arm; and (d) avibratory actuator (40) attached to said body (110), vibrations of saidvibratory actuator being transmitted to said abutment member throughsaid elastic arm.